The use of portable terminals has expanded due largely in part to their convenience. Thus, service providers (i.e., system manufacturers) have responded by developing portable terminals having convenient functions.
For example, certain portable terminals now provide functions, such as phone books, games, schedulers, Short Message Services (SMSs), Multimedia Message Services (MMS), Broadcast Message Services (BMSs), Internet services, electronic mail (e-mail) messages, morning wakeup calls, MPEG-1 Audio Layer 3 (MP3), digital cameras, and the like.
Portable terminals have also been developed to include touch screen panels that provide a means of inputting information. Portable terminals equipped with touch screen panels as the input means may also include functions for controlling the display of the screen, such as zooming in or zooming out the display of the screen. In some cases, this may be provided using a multi-touch function.
The method for using the multi touch function includes recognizing two points touched by user's two fingers and, according to a distance change between the two touch points, zooming in or out a screen display. That is, the multi touch function performs screen zoom-in and out according to a distance change between two fingers touching a screen, so a user has to repeat several times an operation of touching the screen with the fingers, zooming in or out the screen up to a desired level, and separating the fingers from the screen. Repeating the above operation requires a plurality of times of user's input for screen zoom-in and out, and in certain cases, cause undue strain on the surface of the touch screen panel.
Also, a problem may occur where, in certain cases where the user performs the screen zoom-in and out using the multi touch method, the user is inhibited from performing a screen scroll operation at the same time of an operation for zoom-in/out.
Accordingly, there is a need for a screen zoom-in and out function for solving the problem of the multi touch method in a portable terminal.